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C
CarlosRomero14-Alexandrite
14-Alexandrite
January 9, 2021
Solved

Minimize function

  • January 9, 2021
  • 1 reply
  • 5249 views

Hello,

Would anyone be so kind as to point out to me why the MInimize function does not work in this system of equations?

The answer it should give for the variables are: 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 3, 1.

Thank you very much!

Best answer by Werner_E

> Can the objective function be worked with a single variable, w(x)?
Yes, but you would either have to write the full summation indices again as you did it in your original sheet or you will have to resort to the use of the submatrix command. I see no benefit in doing so.

 

You sure have already noticed that the changes you suggest still give a much better (lower) solution that the one you expect:

Werner_E_0-1610252210482.png

 

 

1 reply

W
Werner_E25-Diamond I
25-Diamond I
January 10, 2021

There is something wrong either with your function or with your constraints.

The value of w can be made as low as you wish without violating the constraints! Thats the reason why Mathcad can't find a minimum - the error message about a variable not being defined is nonsense but its the only error message a solve block will ever throw.

The picture shows the elements of x and y which can be enlarged for a lower function value:

Werner_E_0-1610242990483.png

If I add an upper limit for the values in the vectors, the solve block gives a solution, but not the one you expected. So I guess you'll have to check your constraints.

Werner_E_1-1610243093092.png

Mathcad15 file attached.

 

 

 

C
CarlosRomero14-AlexandriteAuthor
14-Alexandrite
January 10, 2021

Thanks Werner for your answer.

Please make the change of the variable in the equation indicated.

One question:

Can the objective function be worked with a single variable, w(x)?CR_Min_90121.jpg

W
Werner_E25-Diamond IAnswer
25-Diamond I
January 10, 2021

> Can the objective function be worked with a single variable, w(x)?
Yes, but you would either have to write the full summation indices again as you did it in your original sheet or you will have to resort to the use of the submatrix command. I see no benefit in doing so.

 

You sure have already noticed that the changes you suggest still give a much better (lower) solution that the one you expect:

Werner_E_0-1610252210482.png

 

 

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